The preparation of paper, such as wallpaper, or cardboard by application of layers of aqueous polymeric dispersions based upon copolymers of styrene with acrylic acid esters and/or butadiene or similar substances, or also in mixtures with emulsions of wax or paraffin, is known. Wallpaper backs pretreated in this manner can be coated with paste having a base of, for example, aqueous methyl cellulose solutions, and can be glued to a surface after a certain swelling time. It is also known to add waxes or pigments such as clay, chalk, or talc to the emulsions to be used for pretreatment. The incorporation of small quantities of water-soluble materials such as starch, dextrin, or similar substances is known as well.
However, these known pretreatment materials have various disadvantages. When a good separation effect is achieved, the side of the paper prepared in the respective manner described, i.e., laminated, has become so hydrophobic that its surface cannot be completely wetted with aqueous paste. The paste contracts on the hydrophobic layer and forms irregular islands. This undesirable phenomenon also can cause premature separation of the bonding. Furthermore, these pretreatment materials close off the surface of the paper so completely that the aqueous paste penetrates it only very slowly. The necessary so-caled swelling of the paper, or cardboard, to be glued on is consequently delayed so long that the paste begins to dry out, starting from the edges of the paper. As a result of this drying out, already applied widths of wallpaper may, for example, pull loose at the joining edges and the seams may buckle. The necessary regluing must be carried out with polymeric dispersions or emulsions and is expensive and especially time-consuming.